Read Sony HCD-DP900D / MHC-DP900D Service Manual online
17
HCD-DP900D
SECTION 5
ELECTRICAL ADJUSTMENTS
0 dB=0.775 V
DECK SECTION
1. Demagnetize the record/playback head with a head
demagnetizer.
2. Do not use a magnetized screwdriver for the adjustments.
3. After the adjustments, apply suitable locking compound to the
3. After the adjustments, apply suitable locking compound to the
parts adjust.
4. The adjustments should be performed with the rated power
supply voltage unless otherwise noted.
5. The adjustments should be performed in the order given in this
service manual. (As a general rule, playback circuit adjustment
should be completed before performing recording circuit
adjustment.)
should be completed before performing recording circuit
adjustment.)
6. The adjustments should be performed for both L-CH and R-
CH.
7. Switches and controls should be set as follows unless otherwise
specified.
• Test Tape
Record/Playback Head Azimuth Adjustment
Tape
Signal
Used for
P-4-A100
10 kHz, –10 dB
Azimuth Adjustment
WS-48B
3 kHz, 0 dB
Tape Speed Adjustment
P-4-L300
315 Hz, 0 dB
Level Adjustment
DECK A DECK B
Note: Perform this adjustments for both decks
Procedure:
1. Mode: Playback
1. Mode: Playback
set
main board
CN301
Pin 3 (L-CH)
Pin 1 (R-CH)
CN301
Pin 3 (L-CH)
Pin 1 (R-CH)
main board
CN301
Pin 2 (GND)
CN301
Pin 2 (GND)
+
–
–
level meter
test tape
P-4-A100
(10 kHz, –10 dB)
P-4-A100
(10 kHz, –10 dB)
2. Turn the adjustment screw and check output peaks. If the peaks
do not match for L-CH and R-CH, turn the adjustment screw
so that outputs match within 1dB of peak.
so that outputs match within 1dB of peak.
3. Mode: Playback
4. After the adjustments, apply suitable locking compound to the
pats adjusted.
Adjustment Location: Playback Head (Deck A).
Record/Playback/Erase Head (Deck B).
Screw
position
position
L-CH
peak
peak
within
1dB
1dB
Output
level
level
L-CH
peak
peak
R-CH
peak
peak
within
1dB
1dB
Screw
position
position
R-CH
peak
peak
MAIN
board
CN301
set
board
CN301
set
test tape
P-4-A100
(10 kHz, –10 dB)
P-4-A100
(10 kHz, –10 dB)
pin 1
oscilloscope
L-CH
R-CH
V
H
waveform of oscilloscope
in phase 45
° 90° 135° 180°
good
wrong
pin 2
pin 3
L
R
forward
reverse
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